Tri-Band Transmitters Ease Telemetry Application Migration to C-Band
Published in Electronic Design
The FCC’s auction, over the last five years, of L-band (1.4 to 1.8 GHz) and S-band (2.2 to 2.4 GHz) microwave frequencies to commercial broadband providers is driving a mandatory migration to the less-populated C-band (4.4 to 5.2 GHz) frequency by U.S. military test ranges (see figure). These test ranges historically used L/S spectrum for telemetering aircraft and missiles.
The auctions provided $2 billion of spectrum reallocation funding. It was funneled to test ranges across the country to fund the development of the ground hardware needed to support the move to C-band. The funding windfall is also helping to drive the development of new technologies, such as more modern modulation schemes.
Today, C-band offers telemetry programs a relatively un-crowded refuge from the rapid build-out of L/S-bands currently underway by the commercial sector, especially as 5G telecommunications starts to come online. What’s more, C-band, unlike the L- and S-bands, has the added advantage of worldwide use, as it’s also commonly used in Europe for telemetry applications. The transition, though, is a work in progress.
In those regions of the U.S. where the L/S bands aren’t yet greatly impacted (in comparison to some major test centers where spectrum crowding is far greater, such as in California), the FCC has allowed a continuation of their use. The agency has also provided timetable extensions to enable a smooth transition to C-band. Currently, some U.S. ranges are still using L/S, while others have made the move to C-band.
Figure: One example of a tri-band (L/S/C) multimode transmitter for aerospace instrumentation applications is Curtiss-Wright’s TTS-9800-2, which provides dual outputs at 10 W.
Another factor slowing the migration to C-band is the fact that nearly 90% of all missile telemetry applications are based on S-band. Not surprisingly, the ranges still have large amounts of S-band equipment inventory that they would like use before completely vacating the frequency. Also, the very large dish-shaped antennas that C-band requires are expensive and take time to install and calibrate.
Many ranges are currently in the process of installing the associated antennas and RF receivers needed to support C-band. They intend to gain experience with the new frequency in advance of the FCC ordering the complete switch over to C-band, so that any potential link issues, etc., will have already been ironed out.
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Paul Cook
Director of Missile Systems, Curtiss-Wright Defense Solutions
Paul Cook is the Director of Missile Systems at Curtiss-Wright Defense Solutions. He has 37 years of extensive design and product line experience in Telemetry Systems. He has held engineering and management positions in design and development, embedded encryption, RF subsystems and data links, engineering and business management, and program management. He has 34 years of experience in the telemetry industry and three years in information assurance Type I CCEP certifications. Paul joined Teletronics in 2007 and, in addition, worked in the telemetry Industry for General Dynamics Corporation, Aydin Corporation, and L-3 Communications Corporation. Paul obtained a BS degree from The College of New Jersey and has various postgraduate courses towards an MBA and program management certifications.
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